Re: [PATCH] 2.6 ide-cd DMA ripping

[Jens Axboe <axboe@suse.de>]

On Sun, Mar 07 2004, Sean Neakums wrote:
> Jens Axboe <axboe@suse.de> writes:
> 
> > On Sat, Mar 06 2004, Sean Neakums wrote:
> >> Jens Axboe <axboe@suse.de> writes:
> >> 
> >> > Hi,
> >> >
> >> > 2.6 still uses PIO for CDROMREADAUDIO cdda ripping, which is less than
> >> > optimal of course... This patch uses the block layer infrastructure to
> >> > enable zero copy DMA ripping through CDROMREADAUDIO.
> >> >
> >> > I'd appreciate people giving this a test spin. Patch is against
> >> > 2.6.4-rc1 (well current BK, actually).
> >> 
> >> Applied successfully to 2.6.4-rc1-mm2, and it works great.  For some
> >> reason, on two different machines, ripping with cdparanoia used to
> >> somehow crowd out the serial port, but now everything just works.
> >
> > cd ripping was highly cpu intensive when it ran in pio, so it's very
> > likely that this screwed up your serial port communication. It doesn't
> > matter with the patch, but had you used hdparm -u1 on your cd device
> > on an unpatched kernel, you would have had better luck.
> 
> I had a look, just for pig iron, and hdparm -u on one of the machines
> reports that it is already enabled.  That machine is SMP with two
> 1.13GHz PIIIs.  I can't check the other machine as the drive in
> question is no longer functional.

Then isr runtime was likely too high, even with interrupt masking
enabled. So just be glad that it works with dma :)

-- 
Jens Axboe